HOUSTON -

A Local 2 investigation has discovered some Houston area gasoline stations charging customers for high-octane gasoline that state tests showed was lower octane than what the stations claimed.

"If you put in lower octane than what your car requires, you could notice a problem," AAA mechanic Steve Van Winkle said.

The Texas Department of Agriculture tests more than 1,000 gas stations each year on a random basis and when customers file complaints.

Inspection records reviewed by Local 2 Investigates showed that since the beginning of 2013, some stations failed state tests.

Among the stations that didn’t pass state lab tests was a station at 14375 Alief Clodine, near the Westpark Tollway and Highway 6. The state listed the station’s name as Shell Food Mart, but a sign on the building said Texas Foodmart. It charged for 93 octane. A state test showed that gas was 6.2 points too low at 86.8.

Gas at a Handi Stop at 14103 Homestead Road, near Highway 59 and Old Humble Road scored 4.2 points below what was promised when the state tested its 93 octane. That gas tested at an octane level of 88.8.

Van Winkle said drivers may know if they have gas with an octane too low for their car if their vehicle makes noises after filling up.

“When you accelerate, you’ll hear a ping noise and possibly you’ll end up with carbon buildup,” Van Winkle said. “That leads to harder starting and poor acceleration.”

The Shop N Go at 1110 Decker Drive in Baytown offered 87 octane, but when the state checked, it tested 1.4 octane points too low.

WATER OR SEDIMENT IN GASOLINE

The state also tests to see if a station’s gas contains water or sediment.

"If there is dirt in the mix it clogs up the fuel filters and doesn't go through the injector," Van Winkle said.

The Shop N Go at 1110 Decker Drive in Baytown had dirt and water in some of its gas, according to state records reviewed by Local 2. The gas station had stopped selling the gas by the time inspectors arrived. It later cleaned up its act.

Van Winkle says no matter where you get your gasoline, don’t fill your tank when the station is getting its gas delivered.

"It is stirring up anything that's in the bottom of the tank and you could be picking it up and putting it in your tank," he said

STATE CAN ORDER STATIONS TO STOP SELLING GASOLINE OR DIESEL

When the state finds concerning levels of sediment or water, or when a gas station’s octane level is below .7 of the posted amount, it can order the station to temporarily stop selling gasoline or diesel.

Below is a map and details of stations the state ordered to close in recent years:

View Stop sell order in a full screen map

To file a complaint about gasoline, fill out the following form online.

If you have a story for investigative reporter Jace Larson email him or tell him about it on Facebook.